An X-Y table apparatus which is adapted to move a work holder in either the X or Y direction is well known in the art and is taught, for example, in Japanese Patent Publication Nos. Sho 62-47555, Sho 63-9477, and Sho 63-13715.
More specifically, a movable table apparatus disclosed in Sho 62-47555 is arranged to stack an X-slide table over a Y-slide table, and thus requires a massive drive mechanism. The movable table unit shown in Sho 63-9477 is fabricated to move an X-Y table to be in line with an X-guide shaft and a Y-guide shaft, which renders the structure complicated and requires a large amount of space. The movable table device illustrated in Sho 63-13715 is also a complicated and massive structure since it utilizes X-Y axes travelling beds, X-Y axes travelling rails, and X-Y movable frames to move a work holder york.
A conventional apparatus that utilizes X-Y tables is shown in FIG. 5 and includes an X-running table 41, a Y-running table 43, and a coupling 42 that couples the Y-running table 43 to the X-running table 41 at an angle of 90.degree.. A work-holder arm 44 is fastened on the Y-running table 43, and 45 indicates a work-holder supported by the work-holder arm 44; i.e., the thing which fastens the Y-running table 43 to slide freely on the X-running table with the coupling 42, is this conventional table. Of course, an X-Y running table in which the X-running table is placed on the Y-running table is also available.
The conventional X-Y running table of FIG. 5 enables movements in both the x and y directions by the illustrated orthogonal placement of the two rectilinear tables. However, such conventional X-Y running tables have certain disadvantages due to this organization of the two rectilinear running tables.
For example the heavier the weight loaded on the table becomes, the thicker the table needs to be to maintain satisfactory stiffness and strength. Also, the number of coupling members that are needed to fasten the two rectilinear running tables in the perpendicular arrangement on the plane is fairly large, as shown in FIG. 6, and the total weight of these coupling members will disturb a light table.
Furthermore, the large number of table components require a considerable time for proper assembly and adjustment.
However, the disadvantages can not be removed because the guide rails and the slide rails are screwed along the sides on the table and so components for a complete X-Y running table are still large in number.